The invention relates to a coupling device between a tape recorder and an attachment, and more particularly to a coupling device for detachably coupling a small size tape recorder with an attachment such as a battery housing, an AC adaptor, a tape speed changer, a radio tuner or the like.
For a small size tape recorder, it is desirable to minimize the overall size for facilitating the convenience of portable use. For this reason, the body of the tape recorder contains a minimum number of components which are essential to the operation thereof. To provide added flexibility in the use of such a tape recorder, an attachment is externally coupled with a tape recorder in a detachable manner. Usually, the attachment is coupled with a mating surface of the tape recorder with a single mounting screw. However, such form of coupling involves difficulty in aligning the abutting surfaces because the single screw is utilized to couple both members. Specifically, the units tend to rotate about the single screw, which prevents an accurate alignment between the opposing abutting surfaces. Thus, it is evident that there is a need for the provision of some anti-rotation mechanism.
On the other hand, the casing of the tape recorder and the attachment is usually molded from a synthetic resin material in order to reduce the cost, and thus their mating surfaces are also formed by molded resin surfaces.
It is to be noted that the individual mating surfaces of the tape recorder and the attachment include a plurality of electrically interconnecting terminals disposed therein so that they can engage each other when the units are coupled together so as to provide an electrical interconnection between the electrical circuit of the tape recorder and the electrical circuit of the attachment.
When the attachment comprises a radio tuner, the attachment is coupled with the tape recorder so as to form a radio set by utilizing an amplifier, a loudspeaker and a power source which are contained within the recorder, and also to enable a signal intercepted by the tuner to be recorded by the tape recorder. However, the use of the power source contained in the tape recorder in such a combination presents several difficulties. Specifically, in a conventional construction, the tuner is turned on by operating a power switch which is provided on the part of the tuner, independently of the condition of use of the tape recorder. However, a user frequently forgets that he has turned on the tuner and leaves it on for a prolonged period of time without operating the recorder, thus wastefully dissipating the portable power source contained in the tape recorder. This is because a conventional tuner is only part of a receiver which becomes complete only when it is combined with a part of the recorder circuit, but cannot function as a receiver when the tape recorder is inoperative. A degree of attention is required of a user, when the power switch represents a small component, in recognizing the position of the power switch in order to confirm that the tuner is in standby condition.
As another aspect, it is recognized that the tape speed during a record/playback operation of the tape recorder be maintained constant. Usually a constant speed control circuit is internally housed within the tape recorder to prevent a variation in the rotational speed of an internally housed motor. However, when transcribing from a recorded tape being reproduced, the usual running speed for such an operation may be too rapid to permit such a transcribing operation. Conversely, when it is desired to grasp the point of a subject contained in a recorded tape, it may be desirable to feed the tape at a more rapid rate. It is obvious that a conventional tape running device cannot be utilized to satisfy these requirements. While it may be desirable to internally house a tape speed changer within the tape recorder, it is difficult, if not impossible, to achieve this without an accompanying compromise in the size of the small size tape recorder.